FIG. 1 is a structure diagram of a traditional cellular radio communication system, and as shown in FIG. 1, the cellular radio communication system mainly consists of a Core Network (CN), a Radio Access Network (RAN) and terminals. Wherein, the CN is responsible for non-access layer transactions such as terminal location update and so on, which are also anchors of a user plane. The RAN includes: base stations, or base stations and a base station controller, and is responsible for access layer transactions such as radio resource management and so on. Physical and logical connections can exist between the base stations according to the practical situation, such as a connection between base station 1 and base station 2 and a connection between base station 1 and base station 3 as shown in FIG. 1, and each base station can be connected to more than one CN node. A terminal, i.e. a User Equipment (UE), refers to various kinds of devices such as a mobile phone or notebook computer which can perform communication with a cellular radio communication network.
An MTC service refers to a service which performs communications between machines. In the MTC service, no people are required to participate, all communications are completed by the machines autonomously, and data are obtained through sensing devices such as a sensor, and then reported to a mobile communication network through a communication module, and connected to a public data network through the mobile communication network. The MTC service can include applications such as logistics monitoring, safety monitoring, tele-medicine detection and remote meter reading and so on. Data of the MTC service are managed by specific servers of mobile operators or special MTC operators, and can be checked by MTC users and MTC managers. In the process, the devices for acquiring the data required by the service are precisely the terminal.
The MTC service introduces a plurality of characteristics such as a Group characteristic and so on different from traditional mobile communications, and when the Group characteristic is activated, the operators' networks can optimize the amount of message of terminals which need to receive the same message based on the Group. The characteristic requires that, when the MTC users subscribe a certain terminal group, the operators set and activate the Group characteristic in subscriber information of each terminal of the terminal group, and store the set subscriber information of each terminal in a Home Subscriber Server (HSS). Here, the HSS is an entity which is responsible for saving identity information, authentication information and authorization information of a user or terminal device in a telecommunication network. According to different situations, the HSS can be used to save the identity information of the user and binding information of the subscriber and terminal device, or can only save the identity information of the user, or can only save the identity information of the terminal device. Wherein, when the HSS only saves the identity information of the user, the binding information of the user and terminal device can be saved by a gateway. In addition, the HSS is also responsible for a subscription database of the user and for executing identity authentication and authorization of the user. A service platform can query the subscriber information of the user or terminal device from the HSS.
In the related art, when a terminal attaches to a network, an MME obtains subscriber information of the terminal from an HSS and saves the subscriber information in local. Wherein, the MME is an entity used to manage user terminal control signalings in the core network and take charge of access control, including: authentication control, identity assignment, user identity and device identity verification, signaling plane encryption, consistency protection with evolved Node B (eNB), conversion of security parameters and Quality of Service (QoS) parameters between 2G/3G and Evolved Packet System (EPS), access grant control, decide whether be able to obtain the requested resources and reserve these resources, lawful interception, mobility management, session management, operations related to EPS bearer and network element selection and so on. Wherein, the identity assignment refers to Globally Unique Temporary Identity (GUTI) assignment and Tracking Area Identity List (TAI List) assignment and so on; the mobility management can be specifically implementing tracking and recording for the current location of the UE.
With regard to the Group characteristic of the MTC service, it is required that the network can perform control on selecting the MME of the terminal group, that is, according to the subscribed group information, the network should be able to provide a mechanism to enable the terminal group to select the same mobility management entity. However, in the related art, there is no such a technical scheme to enable the network to perform control on selecting the MME of the terminal group.